Photographers' Formulary Benzotriazole is used as an organic antifoggant and density depressant in developers.
- Benzotriazole acts as a restrainer without affecting other properties of the developer. It can also be used as a fog restrainer when processing outdated papers.
- When blue-black or cold-black image tones are desired with bromide papers, benzotriazole should be used in addition to, or substituted for, potassium bromide.
- Make a 0.2% solution of benzotriazole (2g benzotriazole in water at 125°f/52°c or higher to make 1 liter) then reduce the bromide to 1/10 or 1/6 strength and use just enough benzotriazole solution to prevent developer stain or fog. A little experimentation may be required.
- The same treatment can be applied to chloride and chlorobromide papers to eliminate any greenish black tendencies and/or achieve a blue-black tone.